Web links

Research Interests

My major research interests involve (1) understanding the populations of
X-ray binary systems, especially in globular clusters and
(2) understanding the physics of accretion in black hole and
neutron star X-ray binary systems, with occasional attempts
to draw connections between accretion physics in stellar
mass and supermassive black holes. I like to keep an eye on
a broad range of topics in astronomy, and I occasionally get
involved with other areas, such as galaxy evolution, as an
offshoot of these two main themes. Most of my work involves
the use of space-based data, but I often supplement this
with ground-based data and I occasionally do a bit of
theoretical work. A few highlights from the first theme are
that I led the discovery of the first globular cluster black
hole X-ray binary, which was found in the galaxy NGC 4472,
and that I was a key team member for the discoveries of the
first stellar mass black holes in globular clusters in our
own Milky Way galaxy. I am also one of the key team members
for the Chandra Galactic Bulge Surve project, coordinating
the radio follow-up and some of the ultraviolet and infrared
follow-up, and the Vista Variables in the Via Lactea survey
project, mostly focusing on the connections with high energy
astrophysics. On the theme of accretion physics, a few of
my key results include the measurement of the luminosity at
which accreting objects show qualitative changes to their
observational appearance (and presumably accretion
geometry), and having helped to pioneer the use of infrared
timing measurements to understand how jets couple to
accretion disks (in work led by Piergiorgio Casella, who was
a Marie Curie fellow working with me at the time). Among
the "offshoot" work, a key set of results came from the
thesis of my first Ph.D. student, Mark Peacock, in which he
produced the most comprehensive, homogeneously analyzed data
set to date on the globular cluster system of M31, the
spiral galaxy in Andromeda, and used the data to help solve
a controversy in galaxy evolution, by showing that only
certain sets theoretical models for how to turn bursts of
star formation into colors were consistent with the M31
data. I also am interested in identifying new techniques
for time series analysis, and figuring out how to apply them
to problems in astrophysics that have not been solved by
traditional time series analysis methodology.